(a) Complete the sentences. Choose the answers from the box. ionising light sound transmitted waves X-rays travel at the speed of ____________________ . X-rays can cause cancer because they are ____________________ . (2) 1 (b) How do X-rays compare with gamma rays? Tick one box. X-rays have a longer wavelength and a higher frequency X-rays have a longer wavelength and a lower frequency X-rays have a shorter wavelength and a higher frequency X-rays have a shorter wavelength and a lower frequency (1) A scientist measured the radiation dose that a person received at different distances from an X-ray machine. The table shows the results. Distance from machine in m Dose in millisieverts/ Mean dose in millisieverts Test 1 Test 2 Test 3 0.5 0.152 0.146 0.155 0.151 1.0 0.039 0.035 0.040 X 1.5 0.017 0.018 0.017 0.017 2.0 0.012 0.007 0.007 0.009 2.5 0.007 0.006 0.005 0.006 Page 1 of 23 Catalyst Tutors
Transcript
(a) Complete the sentences.
Choose the answers from the box.
ionising light sound transmitted waves
X-rays travel at the speed of ____________________ .
X-rays can cause cancer because they are ____________________ .
(2)
1
(b) How do X-rays compare with gamma rays?
Tick one box.
X-rays have a longer wavelength and a higher frequency
X-rays have a longer wavelength and a lower frequency
X-rays have a shorter wavelength and a higher frequency
X-rays have a shorter wavelength and a lower frequency
(1)
A scientist measured the radiation dose that a person received at different distances from anX-ray machine.
in longitudinal waves, the oscillations / vibrations are parallel to the direction of energytransfer
allow direction that the wave is travelling for direction of energytransfer
1
water waves are transverse1
in transverse waves, the oscillations / vibrations are at 90 degrees to the direction ofenergy transfer
ignore references to wave speed, wavelength or frequency
an answer stating that sound waves travel in all directions but waterwaves don’t is insufficient.
1
4
(b)
1
1
frequency = 120 (Hz)
an answer of 120(.481...) scores 3 marks
an answer of 0.12 scores 2 marks1
Page 18 of 23Catalyst Tutors
(c)
Level 3: Relevant points (reasons/causes) areidentified, given in detail and logically linked to form aclear account.
5-6
Level 2: Relevant points (reasons/causes) areidentified, and there are attempts at logically linking. Theresulting account is not fully clear.
3-4
Level 1: Points are identified and stated simply, but theirrelevance is not clear and there is no attempt at logicalthinking.
1-2
No relevant content 0
Indicative content
equipment
• a stopclock / stopwatch should be used to time thewaves
• a metre rule should be used to measure distance
determining the frequency of the waves
• the frequency could be determined by finding thetime for several waves to pass a point
• the frequency could be determined by finding thehow many waves pass a point in a fixed time
• frequency is the average time for one wave to passa point
• frequency =
determining the speed of the waves
• the speed can be determined by measuring thedistance travelled by a wave and the time taken totravel that distance
• the distance used to determine speed should be aslong as possible
• speed = distance/time
determining the wavelength of the wave
• the wavelength can be calculated using the speedand frequency of the wave
• wavespeed = frequency × wavelength
•
•
Page 19 of 23Catalyst Tutors
6
[13]
(a) at least two wave fronts drawn to the right of the glass block, parallel to the other wavefronts and with equal spacing compared with the wave fronts to the left of the glass block
1
5
(b) ray of light refracts towards the normal where it is incident on the glass block1
ray of light does not refract when it exits the glass block1
a normal is drawn on where the ray is incident on the glass block1
the angle of refraction is labelled
lines should be drawn with a ruler1
(c) light travels more slowly (in the glass block than in the air)1
so it changes direction
allow so it bends towards the normal1
(d) the angle of incidence1
the type of glass used
allow the glass block1
(e) the resolution of a normal protractor is too big1
so it could not measure the difference between results
allow so it could not read angles to 2 decimal places1
Page 20 of 23Catalyst Tutors
(f) a longer wavelength gives a greater angle of refraction1
(g) absorbed / reflected1
[13]
(a) wave speed = frequency × wavelength
allow v = f λ1
6
(b)
Level 2: The design/plan would lead to the production ofa valid outcome. All key steps are identified and logicallysequenced.
3-4
Level 1: The design/plan would not necessarily lead toa valid outcome. Most steps are identified, but the planis not fully logically sequenced.
1-2
No relevant content 0
Indicative content
• adjust the bar so that it just touches the surface ofthe water
• adjust motor to produce low frequency wave
• adjust the lamp until the pattern is seen clearly onthe card underneath
• place a metre rule at right angles to the waves
• measure the length of a number of waves (minimum3 waves)
• divide the length by the number of waves to givewavelength
• count the number of waves passing a point in agiven time
• divide the number of waves counted by the time togive the frequency
4
(c) light is reflected off the coin (and travels through the water)
allow correct ray on diagram1
as the light leaves the water its speed increases
allow correct ray on diagram1
(this causes) the light to refract in the direction of the eye1
Page 21 of 23Catalyst Tutors
(d) in longitudinal waves oscillations are parallel to the direction of energy transfer1
in transverse waves the oscillations are perpendicular to the direction of energy transfer1
[10]
(a)
lines should be further apart with the bottom of the wave frontsfurther to the right than the top
1
7
(b) they will speed up1
so wave (fronts) move further apart1
(c) longitudinal waves:
• the oscillations are parallel to the direction of energy transfer1
• show areas of compression and rarefaction1
transverse waves:
• the oscillations / movement are perpendicular to the direction of energy transfer.1
(d) place a floating object / plastic duck on the surface of the water1
it will stay in the same place or only bob up and down if the water doesn’t move1
